1. Field of the Invention
The invention relates to electric machines, and more particularly, to a brush holder assembly for an electric motor.
2. Description of the Prior Art
Brush holder assemblies which control the movement of the brush against the commutator having a critical affect on overall motor performance. There are numerous designs which are currently used by motor manufacturers including assemblies which use constant force springs to control brush movement against the commutator. Some assemblies limit brush loading to the front, while others can be loaded from the back. On the latter, the constant force spring must be removed to install a new brush. Both designs limit brush movement, resist brush cooling, require complicated brush holder designs, and necessitate substantial space for installation. Previously assemblies restrict how the constant-force spring is held in place because the spring manufacturers recommendations limit the approved method to return the constant-force spring to the outside portion of the coiled sections. There is a need for an improved compact brush holder assembly to hold the inside coil sections of the constant-force spring which do not interfere with brush loading. See Applicant's prior U.S. Pat. Nos. 5,977,682 and 5,905,323.